Explosive trip for well devices



Sept. 28, 1943. c BURT I 2,330,265

'- EXPLOSIVE TRIP FOR WELL DEVICES Filed May 16, 1941 010 j] l j! v 020 fi oa W 14 14 3 1 v -1 I I A 1/ 26 31 i 19 25 24- 17 24 2 x INVENTOR: CLAEENCE J5: BURT,

3e 35 E1 BY .4 7 ATTORNEY Patented Sept. 28, 1943 2,330,265 EXPLOSIVE TRIP FOR WELL DEVICES Clarence E. Burt, Los Angeles, Calif., assignor to Baker Oil' ration of Califorma Tools, Inc.,

Vernon, Oalif., a corpo- Applicatlon May 16, 1941, Serial No. 393,751 Claims., (Cl. 166-12) This invention relates to apparatus capable of initiating operation of well devices lowered or supported in a well bore on the end of a wire or other flexible line.

Certain devices, such as bridge plugs, gun perforators, bailers, etc., are lowered into a well bore or casing on the end of a wire line. In some designs, a go-devil or similar weight is dropped down the wire line for engagement with the particular well device to initiate its operation. Obstructions, tight places, or crooked portions in the well boreoften prevent passage of the godevil into engagement with the particular tool connected to the wire line, or the go-devil strikes the device with insufflcient force to initiate its operation, or with a force so great as to inflict damage upon it.

Accordingly, it is an object of the present invention to provide an apparatus which obviates the above noted defects by causing more positive engagement of a go-devil with a well device to institute its operation.

A further object of the invention is to provide a go-devil apparatus employable in connection with a wire line in which it is unnecessary to lower or drop the go-devil' along the wire line to begin operation 01 a well device connected thereto.

This invention has other objects that will become apparent from a consideration of the embodiment shown in the drawing accompanying and forming part of the present specification. This form will now be described in detail, but understood that such detailed denot to be taken in a limited sense, since the scope of the invention isbest defined by the claims appended hereto.

Referring to the drawing:

Figure 1 is a side elevation of a tripping apparatus disclosed in conjunction with a bridge p u r c Figure 2 is a longitudinal section on an enlarged scale of part of the arrangement shown in Figure 1;

Figure 3 is a view similar to Figure 2 with certain of the parts in a different operative position; and

Figure 4 is a diagrammatic view of a circuit employable in connection with the apparatus constituting the present invention.

The apparatus A shown in the drawing is designed for connection to the lower end of a wire line B to initiate operation of a suitable well device C, which in the present instance takes the form of a bridge plug adapted to be set in packed off condition within a well casing D. The apparatus includes a go-devil or similar inertia member ID normally held in retracted position, but adapted to be released by an explosive force for projection toward the well device to produce its operation.

In the specific apparatus illustrated, the wire line B is in the form of a cable having a conductive core ll teminating in a contact I 2 within a firing head l3 threadedly secured to a sub M to which the cable is attached'in any suit.- able manner. A tie rod lower end of the firing head, extending downwardly therefrom through the go-devil III, which is held initially in an upper position adjacent the firing head by a shear screw l6 threaded through the go-devil head I! for receipt within a circumferential groove l8 provided at the upper end of the tie rod l5, This frangible screw normally holds the go-devil l0 inelevated position on the tie rod away from ment with the well device C. downward movement is obtained by imposinga downwardly directed force on its head" I! to shear the screw I 6 and allow its dropping along the tie rod 15 into operative engagement with the particular well device secured to the tie rod.

This force is obtainable by firing a powder charge l9 contained within the firing head l3, which, upon ignition, 'will expand into the'firing chamber 20 for screw 16,

and closes a bore 24 forming the lower end of the firing chamber 20, abutting against a lead sealing disc 25,-which, in turn, engages a steel washer 26 extending across the firing chamber. The lead sealing disc 25 prevents well fluids from entering the firing chamber 20 and dampening the powder charge l9. The powder charge I9 is detonated by a cartn'dge 21 received within a central bore 28'in the upper portion of the firing head. This cartridge 21 is positioned in a slee e 29 yieldably mounted within a retainer 30 a helical spring 3| seating upon a lower shoulder 32 on the retainer and constantly urging the sleeve 29 and cartridge 21 carried thereby upwardly to'hold a contact 33 on the latter in engagement with the contact [2 on the end of the conductor ll.

One form of circuit employable for discharging the powder within the cartridge 21 is dis- IE is screwed into the Its release and vided as a source of current, one terminal being grounded and the other end connected to a lead 35 running to a switch 38. One end oi! the switch is connected to a grounded condenser 31, from where a lead 38 extends to a second switch 39 controlling the discharge from the condenser through the conducting line ii in the wire cable to the contact 33 at the top of the cartridge connected to a heating filament 40 therewithin. The other end or the filament is grounded to complete the circuit.

when the cartridge 21 is to be fired,'the chargfilament 40 becoming heated andsetting oil the cartridge charge, which inturn ignites the'powder charge IS. The gases resulting from the ignition oi the powder charge expand into the firing chamber 20 and exert an explosive force downwardly upon the steel washer 25, lead disc 25,.tripping pin 2| and go-devil ID to, shear the screw l5 and force the go-devil downwardly along the tie rod i5 for initiating operation of the particular well device C to which the tripping apparatus A is connected.

A sufiicient powder charge [9 must be used in the firing head ii to overcome the hydrostatic head of fluid acting upwardly upon the crosssectional area of the tripping pin 2 l and thereby counteracting the explosive force oi. the charge.

The initial pressure in the firing chamber 20 is atmospheric, while the external pressure acting on the tripping pin depends upon the depth to which the apparatus is lowered and the fluid level in the well bore. However, the powder-charge used in the device is ample to overcome this hydrostaticpressure diflerential, and also the resistance offered by the shear screw ii, to produce downward propulsion of the go-devil III. In any event, the powder charge should be insumcient in quantity to inflict damage upon as a result of its detonation.

As specifically disclosed in the drawing, the apparatus is employed for tripping a wire line bridge plug C. The details of such plug may be found in United States Patent 2,225,143. It consists essentially of upper and lower packing members 4| for preventing passage offiuid in both directions between the plug and well casing D, and upper and lower sets of segmental slips 42 for preventing movement of the plug in either direction aftertheir engagement with the wall of the casing. As shown in Figure l, the packings and slips are in retracted position, the tool being supported through a suitable tripping mechanism (not shown), and asleeve 43, which is herein disclosed as secured to a sinker bar 44 attached to the tie rod 1 5. The wire line tripping mechanism also includes a rod 45 extending through the sleeve 43, which has an.anvil or abutment 46 at its upper end projecting outwardly in opposite directions through elongated slots 41 in the sleeve. Upon downward movement of the tripping rod 45 with respect to the sleeve, release of the bridge plug elements 4l, 42 is accomplished, as fully explained in the patent referred This tripping rod 45 is moved downwardly by a generally cylindrical weight 48 having pivoted latches 49 providedwith inwardly directed noses the apparatus v 2,330,265 closed in Figures, in which a battery 34 is pro- 50 resting upon the upper end 5| of the sinker bar 44 to hold the weight in an upper position removed from engagement with the anvil 46. Leaf springs 52 engage the ends of such latches to hold their noses in position on the sinker bar.

It will be noted that the go-devil Iii is initially positioned above the tripping weight 48. Upon release 01' this go-devil as a result of igniting the powdercharge [9, it enters the central bore 48a of the weight 48, its end engaging the inclined noses 50 on the latches to move them outwardly from engagement with the sinker bar 44, permitting the weight 48 to drop downwardly and engage the anvil or abutment 45. The weight is heavy enough to move the tripping rod downwardly within the sleeve 43 to an extent limited by the lower ends of the sleeve slots 41. This action effects-tripping oi the bridge plug and the setting of its packing and slip elements 4|, 42 in engagement with the casing D. Follow ing such tripping action, the firing apparatus, go-devil, tripping weight, sleeve, tripping rod and associated tripping elements are released from the bridge plug and removed to the surface of the well bore.

I claim:

1. An apparatus adapted to be lowered in a well bore on a wire line, including a firing head, a movable weight, releasable means ior prevent ing movement of said weight with respect tosaid head, and explosive instrumentalities within said head for releasing said means to enable dropping v of said weight with respect to said head'to a position wherein said weight initiates operation' of a well device within said well bore.

2. An apparatus adapted to be lowered in a well bore on a wire line, including a firing head having a combustion chamber adapted to contain an explosive charge, piston means normally closing an end of said combustion chamber, a movable weight releasably securedto said head,

' and means for detonating said explosive charge to move said pisto'n'means within said chamber to release said weight from said head.

3. An apparatus adapted to be lowered in a well bore on a wire line, including a firing head having a combustion chamber for containing an explosive charge, a movable weight releasably secured to said head, piston means normally closing said combustion chamber and engageable with said weight, and means for firing said explosive charge, whereby said piston means is forced against said weight to effect its release from said head.

4. An apparatus adapted to be lowered in a well bore on a wire line, including a firing head having a combustion chamber for containing an explosive. charge, a movable weight releasably secured to said head, means normally closing said combustion chamber and engageable with said 7 weight, and means responsive to passage of current through said wire line for firing said explosive charge, whereby said closing means is forced against said weight to efiect its release from said head.

5. An apparatus adaptedto be lowered in a well bore on a wire line; including a firing head having a combustion chamber for containing an explosive charge, a movable weight, frangible means securing said weight to said head, means normally closing said combustion chamber and engageable with said weight, and means for firing said explosive charge, whereby said closing means is forced against said weight to disrupt against said weight to disrupt said frangible means and effect release of said weight from said rod.

7. In an apparatus embodying abridge plug capable of being lowered in a well bore on a wire line and set within a well casing by an inertia member initially held in inefiective position by latches, said apparatus including a depending rod connected to said wire line the combination therewith of means for releasing said latches comprising a go-devil engageable therewith to effect their release, said go-devil being mounted on said rod and explosive instrumentalities for releasing said go-devil to move into engagement with said latches.

8. In an apparatus embodying a. bridge plug capable of being lowered in a well bore on a wire line and set within a well casing by an inertia member initially held in ineffective position by latches, the combination therewith of a firing head having a. combustion chamber for containing an explosive charge, 9. depending rod secured to said firing head, a movable weight mounted on said rod and releasably secured to said head, and means for detonating said explosive charge to release said weight and enable it to move into engagement with said latches to release said in ertia member. I

9. In an apparatus embodying a bridge plug capable of being lowered in a well bore on a wire line and set within a well casing by an inertia member initially held in .ineiiective position by latches, the combination therewith of a firing head secured to said wire line and having a combustion chamber for containing an explosive charge, means including and for connecting said bridge plug to said firing head, a go-devil slidable along said rod, frangible means for releasably securing said go-devil to said rod adjacent said firing head, means normally closing said combustion chamber and engageable with said go-devil, and means for firing said explosive charge, whereby said closing means is forced against said go-devil to disrupt said frangible means and enable said go-devil to move into en gagement with said latches for releasing said inertia member.

10. In an apparatus embodying a bridge plug capable of being lowered in a well bore on a wire line and set within a well casing by an inertia member initially held in ineffective position by latches, the combination therewith of a firing head secured to said wire line and having a combustion "chamber for containing an explosive charge, means including a rod for connecting said bridge plug to said firing head, a go-devil slidable along said rod, frangible means for releasably securing said go-devil to said rod adjacent said firing head, means normally closing said combustion chamber and engageable with said go-devil, and means responsive to passage of current through said wire line for firing said explosive charge, whereby said closing means is forced against said go-devil to disrupt said fra'ngible means and enable said go-devil to move downwardly into engagement with said latches for releasing said inertia member.

CLARENCE E. BURT. 

